Thursday, July 12, 2012

The Spirit of the Lunar Orbiters lives in LOIRP

Newly retrieved high-resolution frame (Lunar Orbiter II-13-H2) showing a roughly 4 km-wide area in south Mare Tranquillitatis, originally photographed, processed and radioed back to Earth by the Lunar Orbiter spacecraft November 18, 1966. It is the center (h2) of three sequential high-res frames captured simultaneous to the imaging of medium resolution Lunar Orbiter observation 2-013. It has been remastered and just released by the remarkable Lunar Orbiter Image Restoration Project (LOIRP) working on the campus of NASA's Ames Research Center in California [Moonviews].

Joel Raupe

Lunar Pioneer

In addition to the five spacecraft the United States presently has in lunar orbit, the legacies left behind by the five Lunar Orbiter spacecraft dispatched in 1966 and 1967, ahead of the manned Apollo landings, collectively amount to a sixth mission, still active and present in more than spirit. Because of the vision and resourcefulness of a special group of engineers and scientists the original tapes containing the raw radio signal returned by the Lunar Orbiters is methodically being processed, essentially for the first time, almost fifty years later. The most recent release of frames originally photographed by Lunar Orbiter II late in 1966 provide us with an easy demonstration of where this growing new library of half-century-old observations fits into our 21st century understanding of the Moon.

Any new craters? On December 21, 2009 the Lunar Reconnaissance Orbiter Camera team swept up much of the territory photographed at high resolution by Lunar Orbiter II in November 1966. The field of view in L2013-H2 is here outlined in yellow. LROC Narrow Angle Camera (NAC) observations M116072806L & R, orbit 2239; angle of incidence 80.6° at 0.96 meters resolution, from 46.3 km [NASA/GSFC/Arizona State University].

Much of the area in the three Lunar Orbiter II high-resolution photographs was surveyed at least once, under a high angle of illumination (80.7°) at slightly better than 1 meter resolution, December 21, 2009. The upper right hand portion of Lunar Orbiter frame 2013 (h2) is also available in the body of Lunar Reconnaissance Orbiter Camera high-resolution Narrow Angle Camera (NAC) observations presently released to the Planetary Data System.

Newly retrieved by the Lunar Orbiter Image Restoration Project (LOIRP), the medium resolution Lunar Orbiter frame 2011 (M) shows a roughly 45 km-wide area in south central Mare Tranquillitatis originally photographed by Lunar Orbiter II, November 18, 1966 (1525 UT). Of the three high-resolution frames of the area, engineered to be captured at the same opportunity, the center frame, h2, is thinly outlined in very pale yellow at the direct center, and is detailed above [Moonviews].

A 3200 square kilometer field of view showing the immediate area of
southeast Mare Tranquillitatis visible in a set of two medium and
three high-resolution Lunar Orbiter photographs newly retrieved and just
released by the Lunar Orbiter Image Restoration Project (LOIRP). The
white rectangle outlines cover the area of the lunar surface in two LROC NAC observations overlapping the
high-resolution Lunar Orbiter II frames. Fields of view in the Lunar Orbiter high-resolution frames
were re-surveyed
at high-resolution by the Lunar Reconnaissance Orbiter, 45 years later. LROC QuickMap at 64 meters resolution, LROC WAC
Global 100 meter monochrome mosaic [NASA/GSFC/Arizona State
University].

LROC QuickMap 4000 meter resolution context view showing the 3200 square km area of the southeast Sea of Tranquility framed in the image immediately above. This part of the Tranquillitatis basin averages out at a bit higher elevation than elsewhere, and is populated by ancient inundated ghost crater rims with the coherent spatter of secondary craters. As our understanding of lunar morphology deepens it has become less clear whether Mare Tranquillitatis constitutes a true basin. Regardless, however, episodic re-floodings by molten material has left behind some of the Moon's deepest mare strata, even if Tranquility is not as clearly defined, horizontally and vertically, as the Serenitatis, Crisium, Nectaris or Imbrium basins nearby [NASA/GSFC/Arizona State University].

The story behind the recovery and retrieval of Lunar Orbiter photography is pretty amazing. The precision design of the spacecraft and their cameras - designed to shoot simultaneous images on film, to then develop that film and televised the result back to Earth - through to the 21st century story labor of love behind how unique and original tapes were housed in a former McDonalds and the nearly extinct drives and software needed even to begin reading those rediscovered tapes were brought online reads like a detective story. The result has been to retrieve images at a quality better than any that had been available for decades, and a virtual sixth mission to complement the present-day 21st century flotilla now in orbit (after a very long drought).

The "older" photography can be used for a variety of important purposes, but in the context of the robust LRO photographic survey, now beginning an unprecedented third year in lunar orbit, no price can be placed on the opportunity to search out the rate of new impacts among the slow changes in the lunar landscape over five decades. And despite its clear strengths as a marvel of engineering and on-time, on budget performance, even the LRO will not be capable of surveying the entire lunar surface at high-resolution (though, so far, the LROC team surveyed much more than half). The release of newly retrieved Lunar Orbiter images. like these "fresh" from 1966, fills some of those gaps nicely, and also provides the opportunity to see the same area of the Moon at high resolution under different lighting conditions.

Meanwhile, the LROC Wide Angle Camera has been able to survey the entire visible lunar surface under a variety of lighting conditions at an extraordinary "medium" resolution.

The original and latter history of the Lunar Orbiter legacy amounts to a heroic story, one made possible by forward-thinking scientists like Gene Shoemaker, and thoughtful people who might have tossed the tapes but instead carefully packed them. Their rediscovery and the dedicated people who rebuilt the capacity to read those tapes makes for interesting reading as well. It also provides us with a lesson about the transitory nature of magnetic and digital media.

If these photos of NASA's Lunar Orbiter Image Recovery Project look suspiciously like they might actually have been taken inside an abandoned McDonalds ... well, that's very observant of you. All of those film canisters you see in the first image are actually spools of 70mm magnetic tape containing the analog originals of images taken by the Lunar Orbiter spacecraft in 1966 and 1967. After sitting in storage for decades—most notably in a barn in California—the tapes were brought to the NASA Ames Research Center in 2007. Since then, some of the originals have been digitized and preserved. (There's a good chance you saw a few in 2008, when the first preserved images were released.) Others are still in process. There's not much funding for this type of work, and it can get expensive, as it involves maintaining extremely rare FR-900 tape drives.Read the entire post at boingboing.net